Removable covers for mobile terminal devices are already known from mobile phones which are currently in use. Patent applications disclosing relevant state of the art are e.g. WO 97/32423, WO 01/86922 A1, EP 1 198 110 A2 and U.S. Pat. No. 6,118,986.
The document WO 97/32423 discloses a clip-on cover for mobile phones having only decorative or design changing functions so that the external appearance of a mobile phone can easily be changed.
The document WO 01/86922 A1 discloses a clip-on cover for mobile phones that comprises distinguishing identity means so that a processor in said phone can identify the characteristics of the cover. The phone can therefore adapt its functionality and the functionality of its display to the functionality of said identified personalized cover. The cover according to this document can comprise a microchip to change the functionality of the phone.
The document EP 1 198 110 A2 1 discloses a clip-on cover for mobile phones that comprise different key arrangements to improve the usability of the phone for preferred usage applications. Such an exchangeable cover is e.g. applied at the 3610i Nokia phone.
The U.S. Pat. No. 6,118,986 describes small pager devices, which can use a small attachable credit card-size keypad to provide a full phone calculator or navigator functionality to said pager device. The credit card sized keypad element can also comprise a display to be adaptable to different kinds of applications.
Phone and communication device personalization, internationalization and customization require many efforts in various handling situations.
All the above approaches for personalization, internationalization and customization have in common that they are not suitable for a market with fast changing communication device models as in the case of mobile phones or handheld computers. Due to short cycles times in which a single telephone of communication device type is manufactured the customization market has nearly no time to react and a certain telephone type may have disappeared before suitable changing covers have been developed.